Manchester United have suffered an injury blow with Kobbie Mainoo out for a “few weeks” and perhaps likely to miss as many as seven matches in a crucial period for Erik ten Hag.

Ten Hag remains under serious pressure after a difficult start to the season for his side, though survived the sack during the international break.

His hopes of an upturn in on-field fortunes have been hit by news of Mainoo’s prognosis, with the midfielder perhaps facing a spell on the sidelines that will extend beyond the next international break in November.

The 19-year-old was forced to withdraw from interim England manager Lee Carsley’s squad last week due to the muscular problem.

Manchester United resume their Premier League campaign against Brentford this weekend before travelling to face Jose Mourinho’s Fenerbahce in the Europa League.

Fixtures against West Ham, Leicester in the Carabao Cup, Chelsea and PAOK follow quickly in a busy period, before another meeting with Steve Cooper’s side in the league before the international break.

Harry Maguire, who picked up an injury in the same game against Aston Villa as Mainoo, is also set to be sidelined for several weeks.

However, Noussair Mazraoui returned to training on Thursday after his recent medical procedure after suffering heart palpitations.

The Morocco international underwent a precautionary, minor corrective procedure to rectify a relatively common condition last week.

He returned to training at United’s Carrington training ground, but this was the first step of his recovery and it is not yet known he whether he will be fit for Saturday’s Premier League visit of Brentford.

Alejandro Garnacho (knee) and Amad Diallo (illness) were also back after missing games for Argentina and Ivory Coast respectively, and look set to be involved against the Bees.